Sound absorbing composition



Patented Mar. 26, 1935 porationof Illinois A N brawingl a plication April swims v "'flrosaoaaf so Ni) A 'soRBm ooMPosrrIoN GeorgenKing, Chicago, 1 11., assignor United a States Gypsum Company, Chicago, lll a cor-g.

e- 35w"- li t sn mber new .j i

18 Claims} (snow-s6) Thisinvention relates-to soundabsorbing ma, terials and has reference more particularlyto a sound absorbing compositionhaving. as a base ia fibrous material, suchasmineralwool, together 7 5 with certain articles manufactured therefrom.

'In the preparation "ofsound absorbing compositions having a fibrous'material as a base, it is desirableto impart to the composition certain qualities which make it suitable for molding into,

shapes such; as tile; slabs, or'ornamental castings of difierent kinds. The composition should be so prepared that the resulting shapes, when applied to the wall or ceiling, will beresistant to.

moisture and yet willbe firm and rigid so asto be structurally strong. It is also important that the resultingacoustical shapes have a high porosity'so that thes'ound absorbing efiiciency will be high.. It is contemplated that my improved com-q positionhis also suitable for use-as a paint or plaster to be applied to walls or ceilings,. in which uses its improved workability and plasticity play an especially important part.

- The object of this invention, therefore, is to provide a sound absorbing composition, having a fibrous'material as a base, which'is suitable for molding into special shapes. V s

Another object of the'invention is to provide a sound absorbing composition having a'granular mineral ,wool base which issuitable foruse as a paint or a plastenor for molding into tile.

A further object of the inventionis toprovide a sound absorbing composition for applying as a paint or plaster or for molding into tile, data, said composition having the properties of providing the paint, plaster or tile with strength and resistance to moisture. V A'still further object of the invention is to provide a sound absorbing composition which has a high porosity, the pores and interstices beingof such a character that a high sound absorbingefiiciency is obtained; also to improve sound absorbing compositions and articlesin other respects hereinafter specified and claimed.

As a fibrous base formy improved composition, I prefer mineral wool because of its nonwilting character or'moisture resistance of the individual fibers, great, connected porosity, re-' sulting in superior sound absorbing qualities, and also because of its fireproof and vermin proof nature. Ihave had especially good results in the use of a special form of mineral WooLknown as granular mineral wool. This is mineral wool in the shape of highly porous little balls of rather irregular shape, and of the size of a pea or larger. This granular wool is :made by mechanically copper sulfate also acts as-a preservative.

processing regular wool; and f is procurableon the market, being familiarly known as, .granulated mineral wool. Wool put into this f ormby; any

able and freeqrunning, -somewhati,,like; cottonseed or corn kernels, wherea'sytheregular: wool; is

matted or felted and is more like cotton in;chaI.-,

acter. Theme of granular wool in my, composi-' tion'makesit easier to dry mix and wet-- mix, and

ter. It should be understood, 'however, that other process that gives *wool of this character is suitable for my purpos e.- Thegranularrwoolispourr .10. easier to mold, into tileor apply as paint or =plas-' Y fibrousimaterials, especially if formed into,.gran-' ules, maybe substituted as=a basejfor the com: position, such as, wood or. .other 'cellulosefibers-or other. lightiweight material which is suitable: I

The other ingredients in"my:- acousticals.com position are:--:s.-'-- I -2., A binder. Fonthisipref erto usea icooked thick-boiling;istarclrgel: forgplantimolded prod-: ucts such as tile. iWhen a dry mixture is'rdesired; such" as 'for plaster and paint to -beymixed-with water on the job, -I prefer an adhesive-prepared from corn or wheatigfiour (mechanically.modi-"* fled) such as is used infoundryicores '-for exam ple theCeres pasteor 'K. B.,p,aste onthe market.

the gum improves the. plasticity and .-i workability of the composition. :::Karaya-.gum1is aym'ate'rial 'similaritd tragacanthzgum in that itisfc'apable of absorbing largefamounts 101' *water :(as high as parts waterto 1 part. gum by weightl-"form ing a'syrupy but not-verysticky solution. I 1 4. An agent to give water resistance- Forthis I prefer to use .an falbuminous substance, such as blood albumin or? animalglua coupled with aLsaIt, suchas copper sulfate. v 1

. Preferablebutnot essential ingredients aiei-Q 5; A?mineral.filler'rtoireduce the tendency of the binder l-jto ,srnolderiv edj such as pyr phyllite.

6. A preservative, beta naphtholz, i'I'he 7-. Coloring imatter; such- .:as raw sienna.

' For some uses, suchZasiOr molding under pressure, the agent or agents :used to :give plasticity, that is the .Karaya gum or cooked starch solu-j V 7 Copper sulfate fGranulated mineral wool g preliminary solutionsare madege a. i M r (a) A cooked starch gel is made by bringingto' 'tion, may be omitted. But a binder must be used,r--forexampie, the modified corn llour mengiven as follows:

tioned above. .p

" The preferred formula for my'cornposition is Pyrophyllite; Beta naphthol -l Water suflicient to give desired p In making up the composition; the following boiling the starch in 1 25lbs. cold water, Prefer-: ably with-some stirring. v

, e j (b) A fluid, gel-insulation;lemm vy 111M045 lba'ot e m water durlngiastagitation} the Karaya' gum, pyrophyllit'e, and raw sienna.

(0), A solution? is made ofthe copper suliat and beta naphtholinfilbs. warm water.

d for) blood albumen is soaked i m a m;

' cold wateri'or 'seye'ral and solution.

111 1118111118 up; the compost f tion', than; and 1b) are mixed thoroughly.- mesmeftionxd) 'isadded to the mixhrtebflufahd (6); Solution (c1 is now added. lhe'teniperature or r il dnot be {over 150 1'; this I eompoflte solution-mineral wool is added and ftoryme ds of mixing may be in a. byimy;

thoroughly mixed in course" other satieia'eei one'fainiliar-Mththeee A plasticmass results vand this maybe imolded-in-perforated'steel' plate formg burlap a being on the bottom ofthegiorma as a backa the "1m place' of the burlap"- other-openmeshi' fabriemay com position" is w the r the'form-and then introduced into dryers where the temperawas maintained at zoo -25o.- r.- untu-ui a or other shapes are A'fter drylngg'the molded product is removed from-themold and the burlap maybe "stripped ofl-trom'the face of theme or'may-b'e left-in slabortiles'arethmcutinto the desired finished sizes 'witheagsaw, ommerwaei-ma onedaee oi 'th'etile isbufled or soasto {sound absorption, byl the interior of the tile. The oppositega'id'eg ofjthe tile maybe bufied or ground'i elightly zto level fit; up; ifs-.5 desired; truinx up; bevelin-,i hegdmie as-ln mannerofwo'rking wood: l a;

Through the: use; of r the i granulated wool, the tacerofjtheiresultlnagtile V is of soft spots consistini-of the balls ,ofthemineral wool which have not been materially bindingiage'nt,

' 7 these ,ballsibe'insasmrated by a harder skeleton:

of containingia largerpercentafie of the binding material.*. sottspots decreased in'isize and qmntityebyincreasing time or thoroughness of of. theiwetimass,

; valleys zor" interstieesibetween :the granules: By proper care in obtaining the desired use: such "valleys, soft spots andharderspotatheeflioiency or vice versasj Also, the userniigranular wool results in: a tilewhichg'accordlna to the degree of wet' have 7 more; or less of absorption of waveslotriiiierentfrequency or pitch can :be controlled toaom ieatent' w or other shap an illustratlveiomiula': 1 Ceres 011' 'K.. B paste Raw sienna- Pyrpphyllite;

qranulated 'mmeral' wool in the above formula both hayethepropertyof It should be understood tileare butled oflQa beautiful variegated appear;

I have found that by a slight modlflcatlonln which the Karaya gum may be omitted from .the formula and a modified corn flour (as 'named above) 'binder'substituted for the cooked I starch solution5the composition'is suitable for molding under pressure. In such a case, pressure is appliedito-the molds by means ofrolls or a ramin the usnalwamth'e arnount of pressure a used determining the density of the resulting My improyed rcomposition, including the gum and cooked amen solution-may alsobe applied V ,to walls in the forrnof paint or plaster; using'a I brush or'trowel respectively." When used for these purpoaea,-. the waterfcontent of the composition maybe altered considerably in the formula above astoigive proper application properties. For such a'palnt'o'r, plaster it is many times de- "-sirable-to a dry mii'rture which may be dry *mixed in the plant and then mixed on thejpb with water for-application, {Infsucliacase I 1- which the Efollbwin'g is prefer a dry mixture 0 flourfadhesiye); Karaya sum-" ;.irr ies redz water resistance may :be dhcaiiied mlfateand 12 lbs; ofgground-cold wtersom e animal gluegor a casein glue maybe instead 1 of tn'eiaaminu l,glue): Theaeoustlcaliabsorptionjof theplasteror paint may be, lrnpitoved by {sanding of! the srn-faoesrof the driediplaster orjpaint The cooked-starch, and the Kara? gum used a form a compound'which materially improves the water fresisting qualities otthe-"composition; some other salts may be; substituted forthe cop- 7 per sulfate; suchas lead atietate-or mercury salts,

such salt's b'eing much superior"to-formaldehyde V or-potassium dichromate. A' casein glue may-be substituted for the-albumin or animal gluebut l 1 H prefer oneof the latter;- The glue also serves as a binding: agent;

7 that other fflllers "may I be substituted for the pyrophyllite' but I prefer the latter because of'itslargef bulk. The prese'i yative beta naphthol maybe rep ced byo ei p ee erv'auves ,such asffalpha-naphthylanune, ietc,

The'copper' sulfateals'o acts as a preventiveto "spoilage'and mildew. Instead of raw. sienna, other coloring, matter maybe, used such asthe Various iron oxide pigments, etc. The coloring matter may penetrate in varying degreesintothe wool granules, according to the degree :of :wet mixing; sol that1when the faces of the resulting I r ance is given thereto, much resembling natural stone.

The'tile may be attached to walls or ceilings by suitable adhesives or by mechanical means' The surface of the applied. tile may be cleaned by refinishing the surface by sand-papering.

Treatment of walls and ceilings of buildings with my composition not only results in valuable Pitch 0; C1 Absorption (percent) .53 .53

I would state in conclusion that while the foregoing description represents a practical embodiment of my invention, I do not limit myself precisely to these details since, manifestly, the same may be considerably varied without departing from the spirit of the invention as defined in the appended claims.

Having thus described my invention, I claim as new and desire to secure by LettersPatentz- 1. A plastic sound absorbing composition including a fibrous material base, a waterproofing agent composed of a mixture of coppersulfate and blood albumin, a gel composed of mixture of cooked starch and Karayagum, and water.

2. A plastic sound absorbing composition in- Globe pearl starch 5 lbs. Karaya gum 1 /4 lbs. Raw sienna 10 ozs. Pryophyllite 3 lbs. Beta naphthol oz.

.Copper sulfate 8 ozs. Blood albumin 1 1b. Granulated mineral wool (4 cu. ft.) 56

lbs. Water to give desired plasticity.

4. A plastic sound-absorbing composition comprising particles of granulated mineral wool, and a binder consisting of starch gel and Karaya gum.

5. A plastic sound-absorbing composition comprising a major portion of particles of granulated mineral wool, a binder capable of cementing said particles together, copper sulfate, and blood a1- bumen. V I e 6. A plastic sound-absorbing composition comprising a major portion of particles of granulated mineral wool, a binder capable ofcementing said particles together, copper sulfate, and blood albumen.

7. A plastic sound-absorbing composition comprising particles of granulated'mineral wool, a binder consisting of starch gel, and analbuminoid water-proofing agent.

8. A plastic sound-absorbing composition comprising particles of granulated mineral wool, a binder consisting of a starch gel and Karaya gum, copper sulfate, and blood albumen.

9. A plastic sound-absorbing composition comprising particles .of granulated mineral wool, a

binder consisting of starch gel and Karaya gum.

copper sulfate and a protein, and a mineral filler. j-

10.'A plastic sound-absorbing composition 7 comprising particles of granulated mineral wool,

abinder consisting of starch gel and Karaya gum, copper sulfate and a protein, and pyrophyl- 11. Aplastic sound absorbing composition that on drying forms a porous sound entrapping surface and which is characterized by connected porosity from the surface through the body portion thereof which comprises particles of granulated mineral wool, a binder therefor comprising a starch gel and Karaya gum, and a water-proofing agent. I

12. A plastic sound absorbing composition that on drying forms a poroussound entrapping surface and which is characterized by connected porosity from the surface through the body portion thereof which comprises particles of granulated mineral wool, and a binder therefor comprising starch.

13. A plastic sound absorbing composition that on drying forms a porous sound entrapping surface and which is characterized by connected porosity from the surface through the body portion thereof which comprises particles of granu lated mineral wool, and a binder therefor capable of cementing said particles together without substantially impairing their inherent porosity.

14. A plastic sound absorbing composition that on drying forms a porous sound entrapping surface and which is. characterized by connected porosity from the surface through the body portion thereof which comprises particles of granulated mineral wool, and a binder capable of cementing said particles together comprising a jelled carbohydrate.

a 15. A plastic sound absorbing composition that on drying forms a poroussound entrapping surface and which is characterized by connected porosity from the surface through the body por-' tion thereof which comprises particles of granulated mineral wool, and a binder capable of ce menting said particles together comprising a jelled carbohydrate and Karaya gum.

16. A plastic sound absorbing composition that on drying forms a porous sound entrapping sur- 7 face and which is characterized by 1 connected porosity from the surface throughthe body portion thereof which comprises particles of granulated mineral wool, and a binder capable of cementing said particles together comprising a starch gel; i

17. 'A plastic sound-absorbing composition that on drying is characterized by connected porosity through the body portion thereof whereupon when its exposed surface is finished off a porous sound-absorbing surface is presented, said composition comprising particles of granulated mineral wool and starch serving as a binder therefor.

18. A plastic sound-absorbing composition that on drying is characterized by connected porosity its exposed surface is finished off a porous sound entrapping surface is presented, said composi tion comprising particles of granulated'ifmineral wool and a binder therefor capable of cementing said particles together without substantially impairing their inherent porosity.

GEORGE D. ,KING.

through the body portion thereof whereupon when 

